GENETIC DIFFERENTIATION AND STRUCTURE OF BOREAL POPULATIONS OF CROSSOCALYX HELLERIANUS (NEES EX LINDENB.) MEYL. IN NORTH AMERICA
Bibliographic record
Abstract
Studying population genetic parameters of dominantly asexual bryophyte species is interesting due to the unique features of their life cycle, such as a relatively short distance dispersal capacity and a lack of the advantages of sexual reproduction. Studying asexual species becomes even more interesting when the study species are also habitat specialists, are rare in part of their global distribution, and have a dominant haploid life cycle. We chose a species that falls into all the above categories, Crossocalyx hellerianus (Nees ex Lindenb.) Meyl.; a minute dioicous epixylic liverwort with dominant asexual reproduction, which inhabits decaying logs and stumps of coniferous trees in boreal and subalpine forests with a circumboreal- subcontinental distribution. The objective of this study is to identify the spatial pattern of genetic variation and structure of C. hellerianus from population (site) to regional (100 km) and intercontinental scales (10 000 km) and to subsequently answer the question, how do the current distribution of the species and dispersal limitations shape the spatial genetic patterns of C. hellerianus? \n \nSamples were collected from three provinces in Canada: Quebec (15 populations, 104 individuals), Alberta (six populations, 50 individuals), and New Brunswick (one population, nine individuals). Using already published data, we compared Canadian and European populations with six populations (99 individuals) from the Czech Republic and four populations (241 individuals) from Finland. Six polymorphic microsatellite markers were used to genotype the individuals. The sequenced data were analyzed for genetic diversity estimations, genetic variation, and population structure parameters using different software packages. \n \nDespite the dominant asexual reproduction mode of this species, we observed a high level of genetic diversity even within colony and population levels. Also, we found some evidence of long-distance dispersal of asexual propagules of the species. In terms of genetic variation and structure, we observed two main clusters in North America and few barriers to gene flow, which is a pattern similar to that found in boreal tree species in North America that were influenced by post-glacial dispersal patterns. The populations from the Gulf of St-Lawrence region were differentiated from the other populations. At the intercontinental level, three significant clusters were observed as Canadian, Czech, and Finnish populations each formed a cluster, although a connection between Europe and North America is suggested via the Gulf of St-Lawrence region. \n \nThe results of this research indicate that the populations of asexually reproducing species can be as genetically diverse as sexually reproducing species. Furthermore, the genetic structure of the species in North America has been shaped by post-glacial dispersal patterns and biogeographic connections between North American and Europe.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".